Square D QO140 - 40A, Circuit Breaker

Engineered for dependable overcurrent protection in demanding electrical environments, the Square D QO140 40A circuit breaker is a practical choice for machines, panels, and control systems that run hard every day.

Where it fits and what it protects

• 40A rating provides targeted protection for feeders and branch circuits in panelboards, switchboards, control panels, and OEM equipment.
• QO family compatibility ensures straightforward replacement and reliable operation within Square D QO panelboards and assemblies.
• Reliable protection in motor control centers—designed to shut down circuits cleanly when overloads occur, helping prevent damage to motors and downstream devices.
• Rugged, industrial-grade construction built to withstand the vibration, temperature variations, and rigors of commercial and industrial facilities.
• Ideal for OEM applications—whether stocking spare parts or integrating into a new build, this breaker fits panels and equipment that require 40A protection.

Use cases and practical scenarios

• Upgrading aging protection in existing QO panelboards or switchgear, ensuring consistent 40A safeguarding for critical circuits.
• Providing dedicated 40A protection on motor feeds or heater circuits within control panels and motor control centers.
• OEM equipment design and manufacturing where a trusted 40A circuit breaker is a core safety component.

Why choose the Square D QO140 over other options

• Part of the proven Square D QO family, the QO140 offers reliable, predictable trip behavior that sensitive equipment and operators can depend on.
• Seamless integration with existing QO installations minimizes downtime during replacement or upgrades.
• Clear, intuitive labeling and compatibility with standard QO mounting practices simplify maintenance and service planning.

Practical guidance for installation and care

• Verify compatibility with your QO-series panelboard, switchboard, or OEM enclosure before installation.
• Install in the correct pole position as specified for your system and ensure all connections meet the facility’s electrical standards.
• Consult your panel’s documentation for proper labeling, replacement intervals, and safety precautions during maintenance.